Method of forming washers



Dec. 9, 1924- 1,518,521

' H. P. KRAFT METHOD OF FORMING WASHERS 'Originai F'ilegl Feb. '20; 1915 Patented Dec. 9, 1924.

- UNITED fST HENRY PHILLIP KRAFT, OE RIDGEWOOD,

NEW JERSEY; EDGAR J. PHILLIPS AND EARL A. DARE EXECUTORS 0F SAID HENRY PHILLIP KRAFT, DECEASED.

marital) or FORMING wnsnans.

Original application filed February 20, 1915, Serial No. 9,537. Divided and this application flied August 16, 1920. Serial No. 403,750...

To all whom it may concern:

Be it known that I, HENRY PHILLIP KnAr'r, a citizen of the United States of America, residing in Ridgewood, in the county of Bergen and State of New Jersey, have invented certain new and useful Improvements in Methods of Forming Washers, of which the followlng is a specification.

This invention relates to packing washcase of leakage through the valve parts, and

in addition to exclude dust, mo1sture,'etc., from the interior of the valve casing. Such caps are customarily provided with a packing of rubber which is carried on the interior of the cap and which is designed to engage the mouth of the valve casing. Such packing washers are necessarily small and consequently liable to distortion in use, es-

, pecially when the capis screwed on to its seat with considerable force. The distortion of the packing interferes'with its efliciency and in the case of thecommon form of valve its inward distortion is often .sufiicient to cause it to engage the deflating pin of the valve, thus opening the latter. This is particularly true in that type of washer which is formed as a dome shaped-member having a recess which is designed to receive the end of the valve stem, which customarily projects above the upper end of the valve casing.

According to the present invention I provide such a dome-shaped packing having a stiffening or strengthening member which is also preferably dome-shaped and is fixed throughout to the washer and which tends to minimize distortion of the latter, thus preventing the above-referred to. Preferably the stiffening member is vulcanized tcg or embedded in the ary 20,1915, and

packing.

The present application is a division of my application Serial No. 9537, filed Februrelates to the method of formin the a-ckin washer described and v claime in said application.

disadvantageous results In the drawings wherein is illustrated one form of the invention,

Figure l is a diametrical section of a valve ca having a washer provided with the present invention, the cap being shown as applied to the end of a valve.

Fig. 2 is an enlarged diametrical section of the washer.

Fig. 3 is a view partly in section and somewhat diagrammatical in form illustratingthe method of forming the washer.

Fig. a is a perspective View of the metal strengthening member.

Referring to the drawin s, let A indicate a valve cap of the well-known Schrader type which'is constructed of sheet metal in such manner as to leave a clear passage through it, the outer end B of the cap constituting a screw driver projection which is adapted to engage the interior valve parts for the purpose of removing them from the casing. Between the screw driver projection B and the screw-threaded body portion C of the cap is a somewhat enlarged chamber D designed receive. the packing washer E- which in the construction shown is dome shaped as best illustrated in Fig. 2. It isusual to provide a sheet metal cup F between the packing and the cap whichconstitutes an anti-friction device whereby when the cap is screwed on the valve casing the cap may rotate without rotating the packing so as to avoid tortional strains on the packing. When the cap A is constructed as shown, that is with a clear passage through it, the washer E- and cup F are imperforat'e so as to prevent fiow of airthrough the cap.

The valve casing is indicated in Figure 1, and it will be observed that its upper edge contacts with the lower face of the packing washer near the outer edge of the latter. Itv

vfore stated frequently becomes distorted to such extent as to be meflicient and so as to engage the valve stem and open the Valve when the cap is applied; According to the present invention the washer is stifi'ened or strengthened so as to oppose an tendency to undue distortion. ThlS may e done in various ways, but it is preferred to use a metallic memberH which is fixed throu hout to the washer, preferably by being eit er shape of the washer. is form of stiffenmg member is illustrated in perspective in Fig. 4. The device may be constructed in .any convenient manner, but the apparatus illustrated in Fig. 3 has been found tobe suit-.

able for the purpose.

In Fig. 3 J represents a plate havin a series of pins K of dome-shaped formation. The plate J andprojections form the lower part of a mould, the upper part being indicated by the reference letter L. In practice the members H .are placed upon the tops of the projections K. and a sheet of unvul- .canized or part1 vulcanized rubber M is placed on top of the series of projections, the upper die L being then forced downwardl The lower die J is formed with a shoul er J which limits the downward movement of the die. L and adjacent to the shoulder-is a recess J which extends around the mould and into which the surplus rubl ber flows. The parts of the mould-are heated duringthis'operation and are continued in heated condition for twenty-five or thirty m'inute's,-the result being that the body of the rubber flows around the caps H, and is moulded into a seriesof caps connected together by aweb of rubber. When the vulcanizing operation is finished the washers are cut from the web and present the appearance of Fig. 2. The ca s H are preferably partly embedded in t e packin al-, thou b they may be only vulcanized t ereto. ii any event suificient rubber should be exposed at the lower face of the packing to constitute a proper, seal for the valve cas- Vhile' the invention has been described in connection with ..a packing for tire valve caps, it will, beunderstood that it is not limited thereto as it may be utilized in connection with packingsfor other devices.

While the preferred form of the invention has been shown and described, it will be understood that various changes may be made therein without departing from the spirit of the invention.

What I claim is 1. The method of forming packing washers for valve caps or the like, which consists in mounting a seriesof stiflening members with their a supporting plate, placing a sheet of rubber .over such series, and applying a mould over said sheet, and then vulcanizing.

2. The method of forming packing washers for valve caps or the like, having stiffening members, which consists in mounting .the stifi'ening members on pins withtheir a supporting edges in spaced relation to edges in spaced relation to plate; a plying a. sheet of rubber over the series 0 stifi'enin members, forcing down a mould on top of said sheet of rubber, and then vulcanizing. 3. The method of formin ers for valve caps or the like, having stifiening members, which consists in mounting the stiffening members on pins with their edges in spaced relation to a supporting plate, applying a sheet of rubber over the series of stiffening members, forcin down. a mould on top of said. sheet of rub er, then "ulcan'izing, and then separating the series of washers from the resu tant thin connecting sheet. I q 4. The method of forming'small rubber articles having reinforcing or stifi'ening members, ries of such stiffening members on pins in spaced relation to a supporting ing asheet of rubber above the series, pressin down a form on top of the sheet of rubber then vulcanizing, and then se arating the series of such articles from t 0 resultant thin connecting sheet. I

.In witness whereof, I have hereunto signedmyname.

packing wash which consists in mounting a seplate apply- 

